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View article: Electro‐Thermally Controlled Active Mechanical Metamaterials with Programmable Stiffness and Nonreciprocity
Electro‐Thermally Controlled Active Mechanical Metamaterials with Programmable Stiffness and Nonreciprocity Open
Active mechanical metamaterials have the potential to revolutionize material capabilities, by switching between different properties. The active mechanical metamaterial presented here can be remotely programmed to switch between compressiv…
View article: Mechanical Metamaterial‐Based Structure with Magnetically Controlled Nonreversibility and Nonreciprocity for Programmable Locomotion
Mechanical Metamaterial‐Based Structure with Magnetically Controlled Nonreversibility and Nonreciprocity for Programmable Locomotion Open
Programmable mechanical metamaterials hold the key to critical innovations in materials science research, by harnessing relatively unexplored nonlinearities that change effective responses. Effective properties of a metamaterial strongly d…
View article: Toughness of Confined Auxetic Foams
Toughness of Confined Auxetic Foams Open
Auxetic (negative Poisson's ratio) materials offer benefits such as impact mitigation, thermal insulation, vibration damping, and reduced deviatoric/shear strain—a key measure of material failure risk. However, the fracture mechanics of au…
View article: Roadmap on metamaterial theory, modelling and design
Roadmap on metamaterial theory, modelling and design Open
This Roadmap surveys the diversity of different approaches for characterising, modelling and designing metamaterials. It contains articles covering the wide range of physical settings in which metamaterials have been realised, from acousti…
View article: Fast optimisation of honeycombs for impact protection
Fast optimisation of honeycombs for impact protection Open
Cellular solids such as honeycombs are often used in impact protection systems. Those with precisely defined geometries allow responses to be programmed to specific functions, but can be costly to design. This article presents an analytica…
View article: Mechanical metamaterials for sports helmets: structural mechanics, design optimisation, and performance
Mechanical metamaterials for sports helmets: structural mechanics, design optimisation, and performance Open
Sports concussions are a public health concern. Improving helmet performance to reduce concussion risk is a key part of the research and development community response. Direct and oblique head impacts with compliant surfaces that cause lon…
View article: Indentation and impact response of conventional, auxetic, and shear thickening gel infused auxetic closed cell foam
Indentation and impact response of conventional, auxetic, and shear thickening gel infused auxetic closed cell foam Open
Auxetic closed cell foams, and highly viscoelastic foams, both show potential to improve impact protection. Specifically, auxetics adapt to the shape of impacting bodies, while highly viscoelastic foams stiffen during severe impacts. So, w…
View article: Free-fall drop test with interchangeable surfaces to recreate concussive ice hockey head impacts
Free-fall drop test with interchangeable surfaces to recreate concussive ice hockey head impacts Open
Ice hockey has one of the highest concussion rates in sport. During collisions with other players, helmets offer limited protection. Various test protocols exist often requiring various types of laboratory equipment. A simplified test prot…
View article: Effect of twist on indentation resistance
Effect of twist on indentation resistance Open
With mechanical metamaterials that display force-torque coupling receiving recent attention, we tested the effect of twist on indentation resistance. We hypothesised that the force required to indent a twisting lattice to a set depth would…
View article: Fabrication of Auxetic Foam in a Pressure Vessel for Sports Applications
Fabrication of Auxetic Foam in a Pressure Vessel for Sports Applications Open
View article: Shear modulus of conventional and auxetic open-cell foam
Shear modulus of conventional and auxetic open-cell foam Open
This work analyses shear moduli of conventional and auxetic open-cell polymer foams. Shear moduli are i) measured directly and ii) calculated by applying elasticity theory for isotropic solid materials, using Young's moduli and Poisson's r…
View article: Effect of Compressive Strain Rate on Auxetic Foam
Effect of Compressive Strain Rate on Auxetic Foam Open
Auxetic foams have previously been shown to have benefits including higher indentation resistance than their conventional counterparts, due to their negative Poisson’s ratio, making them better at resisting penetration by concentrated load…
View article: Fabrication, characterization and analytical modeling of gradient auxetic closed cell foams
Fabrication, characterization and analytical modeling of gradient auxetic closed cell foams Open
Auxetic (negative Poisson’s ratio) and gradient open cell foams have shown promise for their conformability and high impact energy absorption—useful in applications like protective equipment, footwear and prosthetics. Recent methods fabric…
View article: Wearables for disabled and extreme sports
Wearables for disabled and extreme sports Open
This chapter is concerned with the use of wearable devices for disabled and extreme sports. These sporting disciplines offer unique challenges for sports scientists and engineers. Disabled athletes often rely on and utilize more specialist…
View article: List of contributors
List of contributors Open
View article: Auxetic orthotropic materials: Numerical determination of a phenomenological spline-based stored density energy and its implementation for finite element analysis
Auxetic orthotropic materials: Numerical determination of a phenomenological spline-based stored density energy and its implementation for finite element analysis Open
View article: Plantar Pressure Distribution under Uniform and Gradient Foam during Running and Jumping
Plantar Pressure Distribution under Uniform and Gradient Foam during Running and Jumping Open
Auxetic materials have a negative Poisson’s ratio, meaning they contract laterally during axial compression. Auxetics can also absorb more energy during impacts than conventional materials. Auxetic foam was fabricated by volumetrically com…
View article: Effect of Rest Periods on Mechanical Ageing of Running Shoes
Effect of Rest Periods on Mechanical Ageing of Running Shoes Open
Running is a popular form of exercise, although runners are prone to injury from repeated impact. Running shoes can limit impact forces, but they deteriorate with use. Mechanical ageing typically involves repeatedly compressing the midsole…
View article: Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection
Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection Open
Following high profile, life changing long term mental illnesses and fatalities in sports such as skiing, cricket and American football—sports injuries feature regularly in national and international news. A mismatch between equipment cert…
View article: Application of Auxetic Foam in Sports Helmets
Application of Auxetic Foam in Sports Helmets Open
This investigation explored the viability of using open cell polyurethane auxetic foams to augment the conformable layer in a sports helmet and improve its linear impact acceleration attenuation. Foam types were compared by examining the i…
View article: Controlling Density and Modulus in Auxetic Foam Fabrications—Implications for Impact and Indentation Testing
Controlling Density and Modulus in Auxetic Foam Fabrications—Implications for Impact and Indentation Testing Open
Foams are commonly used for cushioning in protective sporting equipment. Volumetrically compressing open-cell polyurethane foam buckles cell ribs creating a re-entrant structure—set by heating then cooling—which can impart auxetic behaviou…
View article: Auxetic Foam for Snow-Sport Safety Devices
Auxetic Foam for Snow-Sport Safety Devices Open
Skiing and snowboarding are popular snow-sports with inherent risk of injury. There is potential to reduce the prevalence of injuries by improving and implementing snow-sport safety devices with the application of advanced materials. This …
View article: A Comparison of Novel and Conventional Fabrication Methods for Auxetic Foams for Sports Safety Applications
A Comparison of Novel and Conventional Fabrication Methods for Auxetic Foams for Sports Safety Applications Open
This study compares fabrication methods for auxetic foam intended for use in sports safety equipment. Thermo-mechanical conversion methods were applied using: i) cubic moulds (150x150x150 mm), ii) cuboidal moulds (150x150x30 mm) & iii) cub…